2008 GL550 transmission issue




Looked for any leaks ..took a few ounces of tranny fluid out.. clean like new no smell. Reset code and took for a test drive.. shifted 1-2-3 gear than threw code .. reset than no reverse..drove up the drive in first and no reverse NO CODES.. shutoff and restarted with a reverse ?? NO CODES? I am getting a little lost and feel like I should start with valve body issue?? Anybody have anything similar or add to my direction thanks Bill
How much fluid was drained and how much refilled?
If you shift manually is the tranny shifting as hard into first?




Torque converter was drained . I use the pump method with temp 113 F .. less than 1/2 qrt came out. I have done approx 10 ..722.9 oil changes with the same method. This was the second change on this vehicle .. bought at 80k miles and changed than 45k miles later both times used approved Amsoil. The car goes between being stuck in 2nd and 1st now. Using my Star system it quit throwing codes. I cannot find much info on error 0893… any help? thanks Bill
Slamming into gear (gear change happening too fast/quickly/uncontrolled) suggests a hydraulic control problem, this mainly is handled in the conductor plate.
Conductor plate failure and replacement is one option. Need to rule out other potential failures.
Do more test driving and try to hold gear using paddles and light throttle. Do this throughout the speed range and hold gear for a good amount of time (1 minute or so). Continue the test and map out each gear change up and down and isolate the problem. All under light throttle.
If you don’t have XENTRY you should have it. You can go into the transmission module and see adaptations. If the adaptations are to the edges of the adjustment windows it will give you direction. An indy shop can do this for you for a diagnostic fee.
Last edited by chassis; Jan 29, 2022 at 01:49 AM.




My next plan is to put it back on the rack and run it.. crack a tranny line loose and see if it has pressure..if yes drop the valve body assembly and look for broken shift lever or stuck pistons???
I was just throwing this issue out there hoping someone knew something about error code 0893? thanks for the help. Bill
There are anecdotal stories of being able to clean the contactor plates with electrical cleaner refilling fluid per the WIS and enjoying forward motion for a limited period of time.
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First code 0893…. indicates a possible valve body but very vague. One post on another forum stated everytime he gets a 0893,0894 he replaces the valve body instantly .
Do you know anything about the National Pro..Valve Body Pro rebuilds? I am going to try and use my TCU/TCM and put it on a rebuilt Valve body..thanks Bill
Last edited by vesiadog; Jan 29, 2022 at 06:58 PM.












My son has a large Ebay store for T129 chassis and I will have Oring kits 16 qty and the 2 orange Silicon electrical plug Orings. MB will not sell the Orings and will only sell the complete Solenoid. I have sized them and inquired about the best material so both will be FKM 75 material. I believe some of the older 722.9 valve bodies have cold weather issues. Here in ohio we had a number of -5 to -12 degree days. Some Viton is only good for +5 degrees.
Ok thanks for any help and ideas. Bill




Except it was after 100 miles driven that day so the tranny was not cold. We have had extremely cold weather here and I am guessing that the extreme cold weather might have something to do with the small blue Orings failures. Bill
Last edited by vesiadog; Feb 11, 2022 at 09:19 AM.




https://cobratransmission.com/722.9-Solenoid-Oring-Kit
https://cobratransmission.com/722.9-Case-Connector-Oring
Last edited by vesiadog; Jun 1, 2022 at 10:02 AM.
I know Cobra Transmission, but the shipping costs for France are expensive ($37).
do you know another site?
or better yet do you know the dimensions of these o-rings?
Thank you very much for your interest in my research.




1.5mm x 8.5mm V75 FKM
for my GL550 I used 8 of each. So far so good.






